Unlike heart attacks, which primarily strike older people and are often survivable, cardiac arrest is 100% fatal if left untreated.

And they can strike out of the blue, much as it did for NBC correspondent Tim Russert, who died tragically in 2008 when a heart attack gave way to sudden cardiac arrest.

More disturbing than the incidence of cardiac arrest in fairly healthy people, however, are the variations in survival rates, which can swing from as low as 3% in some US counties to as high as 20% in others, The New York Times reports.

The shockingly simple procedure that can save lives is none other than CPR — but no standards exist for training people to do it or administering the procedure when it's needed.

A leading killer of Americans over 40

In the US roughly 326,200 people experience sudden cardiac arrest each year, when the heart stops suddenly as the result of a malfunction. A surprising number of them are in good health with no prior indications of heart disease, though the exact figure remains hotly debated.

Cardiac arrest is different from a heart attack, which involves a blocked artery that causes the heart to stop. It also affects a different set of people — middle-aged men and women, a surprising number of whom exercise regularly and eat right. You can think of a heart attack as a "plumbing problem," according to the Sudden Cardiac Arrest Foundation, while you can think of sudden cardiac arrest as an "electrical problem."

For some perspective, here's a chart comparing the number of people in the US who died from SCA in 2012 to the number who died from Alzheimer's disease, assault with firearms, breast cancer, cervical cancer, colorectal cancer, diabetes, HIV, house fires, motor vehicle accidents, prostate cancer, and suicides:

Your chances of survival vary widely based on your zip code

Survival rates for sudden cardiac arrest vary immensely by state and even by county in America. In an ER in Seattle and King County, the Times notes, your average chances of surviving it are nearly 20%. In Detroit, your chances are 3%.

It all comes down to the tools and protocol applied by the people who receive you. Depending on which hospital or ER you end up in, you may get some treatments but not others.

"It's all sort of voluntary — it's a patchwork. And it's created the situation we're in today where survival is very variable depending on where you live," Ben Abella, the Clinical Research Director of the Center for Resuscitation Science at the University of Pennsylvania, told Business Insider. "I think a lot of people think you dial 9-1-1 and you get the same care, but no, it's vastly different."

I think a lot of people think you dial 9-1-1 and you get the same care, but no, it's vastly different.

According to a report done this year by the Institute of Medicine, the average rate of surviving cardiac arrest outside a hospital is just 6%. Even when a patient is treated by first responders, the rate rises to a mere 11%.

The problem? Time — and a lack of standards.

Beating the clock

Healthcare professionals have a precious few minutes to respond to the scene when someone goes down because of a cardiac arrest. The most common phrase the doctors I spoke with use to describe what it looks like when someone is having cardiac arrest is "they drop." And each minute spent responding to the event is critical.

"The biggest thing we can do in terms of helping patients is controlling what happens outside of the hospital before they get in, because those are some of the most critical minutes a patient has," John Greenwood, the Medical Director of the Emergency Department Critical Care Resuscitation Unit at the University of Pennsylvania, told Business Insider.

That's the time the blood isn't circulating and the brain isn't getting the oxygen it needs, and making sure this time is as short as possible can have huge implications for how well a patient recovers.

But the US has no standards, either for training people to apply the life-saving procedures required or for requiring the machinery that could help to be installed in public places like restaurants or shopping malls.

"We're faced with a problem of implementation," said Abella. "We don't know how many Americans have been trained in CPR. You'd think that would be a number we should know, but we don't. We also don't know cardiac arrest incidence and survival. There's no national mechanism to look at that."

The IM report estimates that less than 3% of Americans get CPR training. And they found that defibrillators — the heart-jump starting machines popularized by medical soap operas — are used by bystanders in just 4% of non-hospital cardiac arrests.

"Not all buildings require defibrillators. So even though these have been proven as life-saving devices, we're sort of at the mercy of local businesses. You'd think, well, we have fire alarms that are hardwired into building codes. But defibrillators are not," Abella said.

You'd think, well, we have fire alarms that are hardwired into building codes. But defibrillators are not." Abella said.

Cooper's father, Mark; sister, Michelle; and mother, Lynne, all spent the better part of a month in the hospital with him when he was undergoing treatment for his heart and lungs.
Portia Crowe/Business Insider
One minute he was jogging on a treadmill, the next he was passed out, Cooper told Business Insider.

Like Russert, Cooper suffered from an arrhythmia — a condition causing his heart to beat irregularly. After a neighbor performed CPR, Cooper was brought to Bellevue Hospital in New York where he encountered severe complications.

In the end, only a little known, underfunded technology at Columbia Presbyterian Hospital saved his life.

The technology is called ECMO, and essentially, it works as an external, mechanical heart and lung which together help oxygenate the blood when essential organs stop doing their job. ECMO pumps blood out of the patient's body through a tube, oxygenates it in a machine, and then returns it to the heart through another tube.

Traditional CPR does the same thing, but it can't always be used.

In Cooper's case, his lungs were seriously damaged when doctors induced a coma and put him into therapeutic hypothermia after the treadmill incident to minimize damage to his organs. They had him breathing on a respirator, but then couldn't take him off of it until his lungs had healed. He needed ECMO.

ECMO as part of the solution?

ECMO could have broader uses for others suffering from cardiac arrest.

Two 2015 studies— both done outside the US — found that adding ECMO to traditional CPR (a combination treatment called "E-CPR") appeared to improve survival rates and neurological outcomes for cardiac arrest patients.

The Australian authors of one study concluded: "A protocol including E-CPR instituted by critical care physicians ... is feasible and associated with a relatively high survival rate."

While it's rarely used in the US, the procedure is popular in countries like Japan and South Korea. Adding it in here could make it possible to save more lives and help more people bounce back after cardiac arrest.

"It's not going to be a magic bullet," Abella says of the treatment, "but every little bit helps. We need to be chipping away at this problem from all sides."